Charged-Pion cross sections and double-helicity asymmetries in polarized p+p collisions at √s = 200 GeV

B. A. Cole, Valle, Z. Conesa del Valle, M. Connors, M. Csanad, T. Csoergo, S. Dairaku, A. Datta, G. David, M. K. Dayananda, A. Denisov, A. Deshpande, E. J. Desmond, K. V. Dharmawardane, O. Dietzsch, A. Dion, M. Donadelli, O. Drapier, A. Drees, K. A. Drees, J. M. DurhamA. Durum, L. D'Orazio, Y. V. Efremenko, T. Engelmore, A. Enokizono, H. En'yo, S. Esumi, B. Fadem, D. E. Fields, M. Finger, M., Jr. Finger, F. Fleuret, S. L. Fokin, J. E. Frantz, A. Franz, A. D. Frawley, Y. Fukao, T. Fusayasu, C. Gal, I. Garishvili, F. Giordano, A. Glenn, X. Gong, M. Gonin, Y. Goto, Cassagnac, R. Granier de Cassagnac, N. Grau, S. V. Greene, M. Grosse Perdekamp, T. Gunji, L. Guo, H. -A. Gustafsson, J. S. Haggerty, K. I. Hahn, H. Hamagaki, J. Hamblen, R. Han, J. Hanks, C. Harper, K. Hashimoto, E. Haslum, R. Hayano, X. He, T. K. Hemmick, T. Hester, J. C. Hill, R. S. Hollis, W. Holzmann, K. Homma, B. Hong, T. Horaguchi, Y. Hori, D. Hornback, Song - Jeng Huang, T. Ichihara, R. Ichimiya, H. Iinuma, Y. Ikeda, K. Imai, Awadhesh Kumar Dubey, Mihael Makek, Alexander Milov, Deepali Sharma, Itzhak Tserruya,

Research output: Contribution to journalArticlepeer-review


We present midrapidity charged-pion invariant cross sections, the ratio of the π- to π+ cross sections and the charge-separated double-spin asymmetries in polarized p + p collisions at p√s = 200 GeV. While the cross section measurements are consistent within the errors of next-to-leading-order (NLO) perturbative quantum chromodynamics predictions (pQCD), the same calculations overestimate the ratio of the charged-pion cross sections. This discrepancy arises from the cancellation of the substantial systematic errors associated with the NLO-pQCD predictions in the ratio and highlights the constraints these data will place on flavor-dependent pion fragmentation functions. The charge-separated pion asymmetries presented here sample an x range of ~0.03-0.16 and provide unique information on the sign of the gluon-helicity distribution.

Original languageEnglish
Article number032001
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number3
StatePublished - 1 Jan 2015

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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